Journal articles are often a good place to look after you've decided on a topic (perhaps with the help of some reference tools!). Journal articles are available in both print and online forms. How you access them depends on what date ranges and journal titles are available through different online databases and also your personal preference.
There are few journals that deal specifically with ethnomusicology, but many that might be helpful for particular topics of research. This list is only of journals dealing specifically with ethnomusicology. You can find others by browsing in the music library or the area studies library most closely related to your research or searching the catalog.
There are also some journals available online. Since there is no specific database that deals with world music journals, they can be difficult to find. Looking in Music Index, JSTOR, or Music Periodicals Database can often give you a good start. If you are looking for a particular journal online you can try searching for it on the journal page of the Online Journals & Databases site. And as always, if you run into any difficulties, ask a librarian.